CVE-2026-25733Public exploitNetwork attack vector

Stored XSS via unencoded Custom Rules comments

Published Feb 25, 2026 · Updated Feb 25, 2026

Stored XSS in affected Rucio WebUI releases allows remote authenticated users to execute JavaScript through rule comments. The backend persists the comment field from a Custom Rules request, and the WebUI later inserts it without HTML encoding when a rule is viewed or approved. A low-privileged account plants the payload, but execution requires another authenticated user to open the affected rule; arbitrary script execution grants access to exposed session tokens and the viewer's privileges.

CVSS severity7.3
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in affected Rucio WebUI releases allows remote authenticated users to execute JavaScript through rule comments. The backend persists the comment field from a Custom Rules request, and the WebUI later inserts it without HTML encoding when a rule is viewed or approved. A low-privileged account plants the payload, but execution requires another authenticated user to open the affected rule; arbitrary script execution grants access to exposed session tokens and the viewer's privileges.

The record

CVE
CVE-2026-25733
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
Rucio
Product
Rucio
Classifications
CWE-79, CWE-1004, T1539, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 35.8.3
  2. Affected versionversion=>= 36.0.0rc1, < 38.5.4
  3. Affected versionversion=>= 39.0.0rc1, < 39.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rucio · Rucioversion=< 35.8.3; version=>= 36.0.0rc1, < 38.5.4; version=>= 39.0.0rc1, < 39.3.1

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-1004Sensitive Cookie Without 'HttpOnly' Flag
T1539Steal Web Session Cookie
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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